1. Field of the Invention
The present invention relates to an optical proximity effect correcting method and a mask data forming method in a semiconductor manufacturing process.
2. Description of the Related Art
In an optical lithography process of a semiconductor device manufacturing process, an optical proximity effect is incurred. The optical proximity effect implies that exposure transcription cannot be carried out accurately in the same shape due to light interference between proximity lights adjacent to each other. Therefore, it is required to reduce pattern dimension error caused by such optical proximity effect. The reduction of the pattern dimension error is compensated by correcting the proximity effect, as known in Japanese Laid Open Patent Application (JP-A-Heisei 5-80486). This correction technique is the calculation technique of modifying a line width of a correction target pattern through calculation, as known in Japanese Patent Publication 2616467.
As a technique of correcting the proximity effect, a technique disclosed by Oberdan W. Otto et al, entitled [Optical/Laser Microlithography VII, Vol. 2197, SPIE Symposium on Microlithography 1994], pages 1-16, in a name of [Automated optical proximity correctionxe2x80x94a rulesxe2x80x94based approach] is well known.
In an actual pattern design, there are various sizes (wiring widths) of design patterns, and there are also various space widths and position relations between the design patterns. Here, the combination of a wiring pattern and a contact pattern makes its pattern shape further variable.
If the proximity effect is corrected under such situation, there may be a case that the sufficient proximity effect correction cannot be attained only by adding a correcting pattern having a certain shape to each of the various design patterns. In this case, it may be considered to limit a design rule so that there is no occurrence of the insufficient correction after the addition of the correcting pattern having the certain shape. However, a method of limiting a design rule and a method of validating a design method are not still established. Also, such limitation and validation may result in a drop of design efficiency and largely increase validation process time.
Japanese Laid Open Patent Application (JP-A-Heisei 10-69058) discloses the following technique with regard to an optical proximity correcting method. Not only the optical proximity correction is limited to electrically related structure, but also the individual shape edges are processed. Thus, accuracy of the correction is improved, and also the occurrence of irregularity in design is avoided to thereby reduce the influence on mask manufacture to a minimum. An important edge area in the electrical related structure is analyzed, sorted and processed to thereby receive the optical proximity correction.
Japanese Laid Open Patent Application (JP-A-Heisei 8-321450) discloses the following technique with regard to a mask pattern correcting method. In a mask pattern correcting method for a photo mask used when a pattern is projected to and exposed on a substrate, if a first mask pattern and a second mask pattern adjacent to each other under a certain distance are formed on the photo mask, a pattern correction data is generated by using a shift amount induced at a time of exposing the first mask pattern and the second mask pattern on the substrate and a shift amount induced at a time of etching. Then, a side of the first mask pattern is moved in accordance with a correction amount corresponding to a distance between the first and second mask patterns.
Japanese Laid Open Patent Application (JP-A-Heisei 10-239826) discloses the following technique with regard to a photo mask pattern designing apparatus. It is provided with: a pattern condition input device used for an input of a pattern design rule which implies a condition to extract a photo mask pattern portion to be optimized in a usual photo mask pattern; a pattern extracting device for extracting a pattern cell before the correction of an optical proximity effect, which does not meet the pattern design rule and on which the optical proximity effect correction should be performed; an optical strength simulator for repeatedly performing an optical strength simulation on a pre-optimization pattern cell for a plurality of times; and a pattern optimizing device for optimizing the pattern cell before the correction of the optical proximity effect, in accordance with the plurality of simulation results.
Japanese Laid Open Patent Application (JP-A-Heisei 2-189913) discloses the following technique with regard to a method of forming a pattern of a semiconductor device. This method of forming the pattern comprises: a step of preliminarily forming the patterns by using the elements in which mask patterns where proximity effects occur are formed in advance in various dimensions, when forming the patterns of a semiconductor device by using a mask containing a mask pattern where the proximity effect occurs and a mask pattern where the proximity effect does not occur; a step of determining a relation between the dimensions of these masks and the actually-measured dimensions of the formed patterns; and a step of determining a mask dimension corresponding to a pattern dimension required from the determined relation and accordingly correcting the dimension of the mask pattern in accordance with a difference between both the pattern dimensions.
Japanese Laid Open Patent Application (JP-A-Heisei 10-104818) discloses the following technique with regard to an optical proximity effect correcting method. This method determines an area rate judgment standard as to whether or not it is necessary to correct an optical proximity effect and a judgment distance which receives the influence of the optical proximity effect from another exposure point of an exposure point on the basis of an optical condition in an exposing apparatus in which a photo mask is mounted. This method divides each side of a photo mask pattern into division sides, each equal to or less than a preset length. This method determines an area rate occupied by the photo mask pattern in which a radius centered at a middle point on each division side belongs to a circle of the judgment distance, for each division side. Then, this method compares the area rate of each division side with the area rate judgment standard, and accordingly judges whether or not it is necessary to correct the optical proximity effect for each division side.
The present invention has been made to solve the above-described problems of the conventional optical proximity effect correcting method. An object of the present invention is to provide an optical proximity effect correcting method and a mask data forming method in a semiconductor manufacturing process, which can sufficiently correct an optical proximity effect even under various situations with regard to a size and a shape of a design pattern, and a space width and a position relation between the design patterns.
In order to achieve an aspect of the present invention, an optical proximity effect correcting method in a semiconductor manufacturing process, includes adding a first correcting region around a portion of a first design pattern, the portion facing a second design pattern, and a first corrected design pattern including the first correcting region and the first design pattern; detecting a space between the first corrected design pattern and the second design pattern; judging whether the space is smaller than or equal to a predetermined value; and deleting at least a portion of the first correcting region such that the space is larger than the predetermined value, when the space is smaller than or equal to the predetermined value.
In order to achieve another aspect of the present invention, an optical proximity effect correcting method in a semiconductor manufacturing process, includes: adding a first correcting region around a portion of a first design pattern, the portion facing a second design pattern, and a first corrected design pattern including the first correcting region and the first design pattern; adding a second correcting region around a portion of the second design pattern, the portion facing the first design pattern, and a second corrected design pattern including the second correcting region and the second design pattern; detecting a space between the first corrected design pattern and the second corrected design pattern; judging whether the space is smaller than or equal to a predetermined value; and deleting at least a portion of at least one of the first and second correcting regions such that the space is larger than the predetermined value, when the space is smaller than or equal to the predetermined value.
In this case, the predetermined value is determined based on a resolution of an exposing apparatus when the first corrected design pattern and the second design pattern are exposed by the exposing apparatus.
Also in this case, the predetermined value is determined based on a resolution of an exposing apparatus when the first and second corrected design patterns are exposed by the exposing apparatus.
Further in this case, the first design pattern has a substantially rectangular region, and the optical proximity effect correcting method, further includes: detecting a remaining region of the first correcting region, the remaining region having a dimension smaller than or equal to a specific value; and deleting the remaining region from the first correcting region.
In this case, an optical proximity effect correcting method, further includes: detecting a remaining region of each of the first and second correcting regions, each of the first and second correcting regions having a dimension smaller than or equal to a specific value; and deleting the remaining region from each of the first and second correcting regions.
Also in this case, the remaining region is a region which remains after deleting at least a portion of the first correcting region.
Further in this case, the remaining region is a region which remains after deleting at least a portion of the at least one of the first and second correcting regions.
In this case, the predetermined value is determined based on a resolution of an exposing apparatus when the first corrected design pattern and the second corrected design pattern are exposed by the exposing apparatus.
Also in this case, the first correcting region is a single region to surround an end portion of the first design pattern, and the second correcting region is a single region to surround an end portion of the second design pattern.
In order to achieve still another aspect of the present invention, an optical proximity effect correcting method in a semiconductor manufacturing process, includes: detecting a plurality of corner portions included in a pattern; detecting, as a first side, one of sides provided between the plurality of corner portions; detecting a second side parallel with the first side in the pattern; detecting at least one of the plurality of corner portions contacting at least one of the first and second sides, as a specific corner portion; detecting a length of a side, as a specific side, adjacent to and normal to one of the first and second sides; judging whether the detected length is larger than or equal to a predetermined value; extending the first side to a position corresponding to the specific corner portion in contact with the specific side to form a third side when the detected length is larger than or equal to the predetermined value; determining a correcting region based on the third side; and adding the correcting region to the pattern.
In this case, an optical proximity effect correcting method, further includes: designating a region around a specific pattern, at least a portion of which is in contact with the pattern; and wherein each of the steps of the optical proximity effect correcting method is performed in the designated region, and the pattern is a wiring pattern and the specific pattern is one of a contact pattern and a through hole pattern.
Also in this case, an optical proximity effect correcting method, further includes: designating a region around a specific pattern, at least a portion of which is in contact with the pattern; and wherein each of the steps of the optical proximity effect correcting method is performed in the designated region, and the pattern is a contact pattern and the specific pattern is a gate pattern.
Further in this case, the designated region is surrounded with the specific pattern.
In order to achieve yet still another aspect of the present invention, a mask data forming method in a semiconductor manufacturing process, includes: adding a correcting region to a design pattern based on a first data indicating at least a portion of the design pattern to form a first corrected pattern; correcting the correcting region based on a second data different from the first data to form a second corrected pattern; generating a mask data based on the second corrected pattern; and detecting a defect of the mask data, and wherein the correcting includes correcting the correcting region such that a data indicating one of a projection portion and a concave portion which are smaller than a predetermined size, is not detected as the defect.
In order to achieve another aspect of the present invention, a mask data forming method in a semiconductor manufacturing process, includes: adding a correcting region to a design pattern based on a first data indicating at least a portion of the design pattern to form a first corrected pattern; and correcting the correcting region of the first corrected pattern based on a second data different from the first data to form a second corrected pattern; generating a mask data based on the second corrected pattern, and wherein the correcting includes deleting at least a portion of the correcting region such that a space between the correcting region and one of another design pattern and another first corrected pattern is not smaller than a predetermined value.
In order to achieve still another aspect of the present invention, a computer readable recording medium for recording a program for a process includes: adding a first correcting region around a portion of a first design pattern, the portion facing a second design pattern, and a first corrected design pattern including the first correcting region and the first design pattern; detecting a space between the first corrected design pattern and the second design pattern; judging whether the space is smaller than or equal to a predetermined value; and deleting at least a portion of the first correcting region such that the space is larger than the predetermined value, when the space is smaller than or equal to the predetermined value.
In order to achieve yet still another aspect of the present invention, a computer readable recording medium for recording a program for a process includes: adding a first correcting region around a portion of a first design pattern, the portion facing a second design pattern, and a first corrected design pattern including the first correcting region and the first design pattern; adding a second correcting region around a portion of the second design pattern, the portion facing the first design pattern, and a second corrected design pattern including the second correcting region and the second design pattern; detecting a space between the first corrected design pattern and the second corrected design pattern; judging whether the space is smaller than or equal to a predetermined value; and deleting at least a portion of at least one of the first and second correcting regions such that the space is larger than the predetermined value, when the space is smaller than or equal to the predetermined value.
In this case, the predetermined value is determined based on a resolution of an exposing apparatus when the first corrected design pattern and the second design pattern are exposed by the exposing apparatus.
Also in this case, the predetermined value is determined based on a resolution of an exposing apparatus when the first and second corrected design patterns are exposed by the exposing apparatus.